Michael B. Williams spent nearly two years helping to run a trade group focused on expanding sales of firearm silencers by American manufacturers. As a White House lawyer, he pushed to overturn prohibitions preventing gun sales to private foreign buyers, raising the issue with influential administration officials and creating pressure within the State Department, according to current and former government officials. On Friday July 10 2020, the State Department lifted the ban, and a longtime industry goal was realized. The change paved the way for as much as $250 million a year in possible new overseas sales for companies that Mr. Williams had championed as general counsel of the American Suppressor Association. An examination of Mr. Williams’s rise from trade group advocate to West Wing lawyer reveals that White House tumult and turnover created opportunities for him. After joining Mr. Trump’s campaign in 2016, Mr. Williams, at age 30, became an assistant deputy general counsel at the Office of Management and Budget, then led by Mick Mulvaney. In the spring of 2019, not long after Mr. Mulvaney was elevated to acting White House chief of staff, Mr. Williams joined him as counselor and a deputy assistant to the president. His brother, Knox Williams, started American Supressor and serves as its president and executive director, and the two have remained in regular contact. A Georgia native and Eagle Scout, Mr. Williams worked as a law clerk for the National Rifle Association before graduating from George Washington University Law School in 2014. Soon after, he went to work at the American Suppressor Association, which his brother had co-founded three years earlier. The Williams brothers also tried to influence silencer policies in various states, including in New Hampshire, where both registered as lobbyists in 2015.